QED Effects on Kerr Black Hole Shadows immersed in uniform magnetic fields

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In this work, taking the QED effect into account, we investigate the shadows of the Kerr black holes immersed in uniform magnetic fields through the numerical backward ray-tracing method.

• We introduce a dimensionless parameter $\Lambda$ to characterize the strength of magnetic fields and studied the influence of magnetic fields on the Kerr black hole shadows for various spins of the black holes and inclination angles of the observers.
• In particular, we find that the photon "hairs" appear near the left edge of the shadow in the presence of magnetic fields.
• The photon hairs may be served as a signature of the magnetic fields.